It is believed that UK customers could end up paying a total of £1.3 billion towards the £12 billion project, on top of the fifth of their bill that already goes towards supply maintenance.
This could see bills rising by around £50 over the next five years, consumer group Energywatch has claimed. The news follows the first decline in gas prices recently for three years.
Regulator Ofgem told the Express: "While Ofgem is forcing the companies to be as efficient as possible, the costs gas distribution networks face for delivering a nationwide gas mains replacement programme to improve safety are also rising."
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